assume cs:code,es:data
data segment
	a db 1,2,3
	b dw 0
data ends

code segment
start : mov ax,data
		mov es,ax
		mov si,0
		mov cx,3
	s:	mov al,a[si]
		mov ah,0
		add b,ax
		inc si
		loop s
		mov ax,4c00h
		int 21h
code ends
end start